Refrigerant evaporator



M y 1934- J. R. REPLOGLE REFRIGERANT E ZVA PORATOR Filed Dec. 14. 1931 2 Sheets-Sheet l INVNTOR @7577 Pepioyie. HEY

W gupzuwm ATTORNEYS Patented May 29, 1934 REFRIGERANT EVAPORATOR John R. Replogle, Detroit, Mich., assignor, by mesne assignments, to Copeland Refrigeration Corporation, Mount Clemens, Mich., a corporation of Michigan Application December 14, 1931, Serial No. 581,037

12 Claims. (01. 62-126) This invention relates to refrigeration apparatus and has to do particularly with structures employed in such apparatus for evaporating refrigerant liquid.

An object of the invention is to provide, in refrigerating systems, a refrigerant evaporating unit in which the temperature of the parts thereof will be substantially constant throughout.

Another object of the invention is to employ a refrigerant evaporating conduit in which the temperature ordinarily varies from one end thereof to another in such manner as to provide a refrigerant evaporating unit in which the temperature of the parts with which said evaporating conduit is in thermal contact will have an average value which is substantially constant from one extremity of the aforesaid conduit to another.

Another object of the inventionis to assemble, in an insulated cabinet, the elements of a refrigerating evaporating unit in such novel manner as to render the entire structure more pleasing in appearance, more serviceable and more efflcient in operation than such units have been in refrigerators heretofore employed.

Prior to the invention, in building refrigerant evaporating units, it has been the custom to wind a long refrigerant evaporating conduit in the form of a coil and then to employ this coil both for cooling the interior of a refrigerator and for freezing water and desserts or other substances inserted in trays in the interior of the coil. Sometimes these coils were employed for directly cooling the air and also in direct contact with the freezing trays while in other instances the coils were embraced in brine tanks or other indirect heat exchange devices. When a refrigerant liquid was expanded into one end of the coil the transfer of heat from the coil to the refrigerant would vaporize most of the latter at a relatively constant temperature depending upon the vaporpressure in the system. As soon, however, as the refrigerant was vaporized it would pass onwardly into other portions of the conduit where the liquid refrigerant had not yet reached and in such regions the transfer of heat from the conduit to the vapor would increase the temperature of the latter progressively as it approached the conduit end. Obviously, the more the temperature of the refrigerant vapor increased the less heat would be extracted from the conduit and, consequently, the temperature of an evaporating unit in which such conduit was employed would vary as the temperature of the conduit. With an evaporating unit having the different parts thereof maintained at different temperatures it would of course be impossible to refrigerate as efficiently as though the entire unit were maintained at the temperature of the part thereof having the lowest temperature, in view of which fact it has been found advisable to construct considerably larger evaporating units than would have been required had the temperature been maintained constant throughout.

It has also been customary heretofore in the construction of refrigerant evaporating units to apply thereto brackets and other fastening devices by which said units were suspended from the tops of refrigerators by the employment of bolts, screws and other expensive and unsightly appurtenances.

This invention embraces an evaporating unit for refrigerating systems in which a portion relatively near the beginning and a portion relatively near the end of a refrigerant evaporating conduit employed therein is in contact with practically every part of the evaporating unit, thus maintaining an average temperature throughout which is substantially constant in every portion of the structure.

For securing such evaporating units within a refrigerator, means is provided forsupporting the rear end of the evaporating unit upon the rear wall of a refrigerator and for securing the front baffle of the unit rigidly with respect to the refrigerator top wall.

For a better understanding of the invention, reference may now be had to the accompanying drawings forming a part of this specification, in which:

Figure 1 is a diagrammatical illustration of a refrigerating system in which an evaporating unit embracing the principles of this invention is employed;

Fig. 2 is a fragmentary vertical cross sectional view of a refrigerator employing a refrigerant evaporating unit embracing the principles of the invention;

Fig.3 is a cross-sectional view of the evaporating unit disclosed by Fig. 2 and is taken substantially on line 3-3 thereof;

Fig. 4 is a fragmentary cross-sectional view of the evaporating unit illustrated by Figs. 2 and 3 and is taken substantially on line 44' of the former;

Fig. 5 is a vertical sectional view of a refrigerator in which another refrigerant evaporating unit embracing the principles of the' invention is employed;

Fig. 6 is a fragmentary front view partly in slightly different form of evaporating unit such as that illsutrated by any of the figures of the drawings which might represent a section through any portion of one of the structures where a refrigerant evaporating conduit is employed.

Referring particularly to Fig. 1, a refrigerating system 10, employed in practicing the invention, comprises a compressor 11 having drivingmechanism 12 by which the compressor is driven by an electric motor 13. A condenser\14, connected to the compressor 11 by a conduit 16, receives compressed refrigerant through the conduit 16 and by exchanging heat with the atmosphere or other suitable cooling fiuid, the vapor is changed to a liquid and is then discharged through a conduit 17 into a liquid refrigerant receiver 18. From the receiver the refrigerant liquid is discharged through a liquid line 19 and an expansion or pressure reducing valve 21, into a refrigerant evaporating unit 22 where the liquid is again vaporized and is returned to the low side of the compressor 11 through a suction line.

In the structures disclosed by Figs. 2, 3 and 4, the evaporating unit 22 comprises a pair of metallic shells 24 and 26 around which a relatively long refrigerant evaporating conduit 27 is wound. The conduit 27 consists of a pair of sections 28 and 29, having a loop 31 at one end thereof and a pair of couplings 32 and 33 at the opposite end. Each of the sections 28 and 29 is wound helically around the sleeves 24 and 26 from one extremity thereof to the other and in such manner that the adjacent portions of the convolutions of conduit on each of the sleeves will lie between each other and such portion of any convolution will have a thermal contact with both sleeves. The expansion valve 21, or other suitable metering device, communicates with one end of the conduit 2'7, as for example the end having the coupling 32, while the opposite end is connected by the coupling 33 to the suction line 23. A thermostat or other suitable controlling device (not shown in Figs. 1 to 4) is fastened in thermal contact with the suction line end of the conduit 27 in a region remote from the end thereof connected. to the expansion valve 21.

Adjacent the front end of the evaporating unit 22 and on opposite sides thereof, is secured a pair of curved bars 34 and 36 having lugs 37 projecting outwardly therefrom in which the ends of stud bolts 38 are adapted to be threaded. Between the lugs 3'7 and a baflle 39, supported on the outer ends of the screws 38, are spacing tubes 40 surrounding intermediate portions of the bolts 38 for maintaining the baflle outwardly against the heads of the screws. Openings 41 and 42 formed in the baffle 39, directly in front of the sleeves 24 and 26, permit the insertion of freezing trays 43 and 44 respectively into the aforesaid sleeves therebeyond.

The opposite end of the evaporating unit 22 is likewise provided with a pair of bars 46 secured in any suitable manner to the opposite outer surfaces thereof and these bars likewise are provided with a plurality of struck out lugs 4'7. Bolts 48, projecting through a rear removable wall 49 of an insulated refrigerator cabinet 51 are threaded into openings formed in the lugs 47 and hence secure the evaporating unit 22 rigidly in position against the aforesaid refrigerator back wall. Tubular spacing members 52 the'portions of the bolts 48 between the back wall 49 and the lugs 47 not only hold the ends of the bolts 48 to prevent bending thereof and lugs 47 but by being compressed between the lugs and the rear wall they relieve the load on the edges of the sleeves 24 and 26 abutting the rear wall.

Resilient gaskets 53 compressed between the edges of the rear wall 49 and abutting portions of I the other walls of the refrigerator 51 prevent theflow of air between the adjacent edges of said parts and the consequent loss of refrigeration which might otherwise result.

In order to provide good thermal contact between the conduit 27 and the sleeves 24 and'26, the conduit may be welded or soldered to the sleeves, if desired, or may be secured thereto, as illustrated by Fig. 4, by employing a coating of vitreous enamel on all the surfaces of the sleeves and tubes to form a bond between the adjacent surfaces through which heat is conducted from the sleeve to the refrigerant within the conduit.

It will be observed that substantially every region of the sleeves 24 and 26 is in thermal contact with both of the conduit sections 28 and 29, and that such contacting portions of said sections are substantially equally distant from the inlet and outlet endsof the conduit.

Assuming the most'unfavorable condition, that is, one in which the temperature of an evaporating conduit would tend to increase progressively from the inlet to the outlet end thereof, it is apparent that the average temperature of the conduit sections would tend to equalize at substantially all distances from the ends thereof. Inasmuch as all portions of the sleeves 24 and 26 are in thermal contact with some portions of the conduit sections 28 and 29, the temperature of such sleeve portions ordinarily will not be greater than the average temperature of the entire evaporating conduit.

In the structure disclosed by Figs. 5 to 8 the evaporating unit 22 comprises a single inner shell 56 which is divided by shelves 57 and 58 into a plurality of freezing compartments for the reception of ice trays 59, 60 and 61. The exterior of the shell 56 is substantially surrounded from one end to another by an evaporating conduit 62 which comprises a pair of parallel sections 63 and 64 having a loop 66 at one extremity thereof. The sections 63 and 64 are so wound as a unit upon the sleeve 56 that any portion of the sleeve is in close association with portions of the sections substantially equally distant from the ends thereof in which refrigerant is supplied and exhausted.

The sections 63 of the conduit 62, in the region adjacent the rear end of the sleeve 56, has one more convolution than the section 64 in order that the first mentioned section shall have two adjacent convolutions between which the bulb 67 of a thermostatic switch 68 is confined by a bracket 69 in thermal contact with both of said end convolutions and the bulb. Couplings l1 and 72 respectively join the free ends of the sections 63 and 64 of the evaporating conduit 62 to the suction and liquid lines 23 and 19, of the refrigerating system disclosed by Fig. 1.

The rear end of the evaporating unit 22 disclosed by Figs. 5 to 8 is supported by a bracket 73 secured to the lower part thereof, on the outside surface of the last few convolutions of the'conduit sections 63 and 64, and by a bolt 77 to the rear wall 74o! a refrigerator 76.

The front end of the evaporating unit is provided, at the corners of the sleeve 56, with a plurality of brackets 78 upon which a front baflle 79 is secured by screws 81. The two vertical sides of the baffle 79 are flanged rearwardly as indicated at 82 and such'fianges support one or more hooks 83 for partially supporting refrigerator shelves not shown.

The central portion of the bailie is provided with a flanged opening 84 through which access may be had to the freezing trays contained within the sleeve 56.

A bracket 86 secured on the rear of the baffle '79 immediately above the sleeve 56 has a vertically disposed rear end portion 8'1 to which the thermostatically controlled switch 68 is secured by bolts 88.

Just above the flange 86 the front baffle 79 is provided with a removable cover 89 for an opening through which access may be had to the thermostatic switch 68. The front of the removable cover 89 also is employed as a dial for a switch controlling arm 91 positioned thereon.

The upper edge of the baffle 79 is flanged rearwardly as indicated at 92-and such flange is secured by bolts 93 to an upper wall 94 of the refrigerator 76.

A power line 95 connected by a detachable coupling 96 to the thermostatically controlled switch 68 supplies power to the motor 13, when the elements of the switch are effected in a predetermined manner by the temperature in the interior of the refrigerator 76 or by the temperature of the evaporating unit 22.

In Fig. 8 is illustrated an evaporating unit section in which the shell or sleeve 56 is helically corrugated, as indicated at 97, to provide parallel grooves in which the evaporating conduit sections 63 and 64 are disposed. The conduit 62 may be welded or otherwise secured tothe sleeve 56 or it may be retained in its proper position within the grooves 97 by a suitable coating of finishing material 98 such for example, as vitreous enamel now generally employed in the construction of structures of this character.

It will be apparent that the evaporating unit disclosed herein will be more uniform in temperature than evaporating units of a similar character heretofore employed and that it will be possible to utilize a relatively large amount of refrigerant evaporating conduit in an evaporator without the relatively serious consequences heretofore encountered.

While only a plurality of forms of the invention have been described in detail in this specification, it will be apparent to those skilled in the art that the invention is not so limited but that various other forms of the invention may be embraced within the spirit thereof and the scope of the appended claims.

I claim:

1. A refrigerating system comprising a refrigerant evaporating conduit having a pair of parallel sections wound in the form of approximately coextensive helices to provide an interior freezing compartment and an exterior air cooling surface and means for supplying liquid refrigerant to and for exhausting vaporized refrigerant from the adjacent and corresponding ends of said conduit sections.

2. A refrigerating system comprising a freezing tray receiving sleeve having a pair of conduit sections joined at one end and wound in parallel 3. A refrigerating system comprising a sleeve having a pair of parallel and spirally formed grooves forming a double. thread in the exterior surface thereof and extending substantially from one end of the sleeve to another, a refrigerant evaporating conduit disposed throughout substantially the entire extent of said grooves and means for supplying liquid refrigerant to and for exhausting vaporized refrigerant from the opposite ends of said conduit.

4. A refrigerating system comprising a sleeve having a groove formed in the surface thereof, a refrigerant evaporating conduit disposed within said groove and a coating of vitreous enamel upon the exposed .surfaces of said conduit and sleeve for securing said two elements rigidly to gether and means for supplying liquid refrigerant to and for exhausting vaporized refrigerant from said conduit.

5. A refrigerating system comprising a sleeve having a plurality of convolutions of refrigerant evaporating conduit wound thereon, said conduit convolutions alternately comprising portions of a pair of parallel sections of said evaporating conduit, an extra convolution of said conduits at one portion of said sleeve to provide two adjacent convolutions of the same conduit section, a thermally actuated switch for causing cyclic operation of said refrigerating system associated with said adjacent conduit convolutions, means for exhausting vaporized refrigerant from the end of said conduit section having said adjacent convolutions therein and means for supplying liquid refrigerant to the adjacent end of said other conduit section.

6. A refrigerating system comprising a heat insulated cabinet adapted to be cooled by the circulation of air internally thereof, a sleeve disposed in said cabinet and having a relatively long depression formed in the exterior surface thereof, said sleeve being adapted to provide a freezing compartment internally thereof and to cool and circulate the air within said refrigerator by the exchange of heat through the exterior surface thereof, a refrigerant evaporating conduit disposed in said depression in said sleeve and extending substantially from one end thereof to another, a layer of porcelain embracing said sleeve and conduit and bonding them together and means for supplying refrigerant liquid to and for exhausting vaporized refrigerant from the opposite ends of said conduit.

'7. A refrigerating system comprising a heat insulated cabinet adapted to be cooled by the circulation of air internally thereof, said cabinet having a door opening formed therein, adapted to render the contents thereof available, a refrigerant evaporating unit within said cabinet for cooling said air therein and disposed immediately inside said door opening, a sheet metal baiile facing said door opening and covering the front of said evaporating unit for obstructing the latter from view through said door opening, said bafile having an opening formed therein rendering said evaporating unit accessible, and means for detachably securing said bafile to the front end of said evaporating unit and to a wall of said insulated cabinet for supporting said evaporating unit within said cabinet.

8. A refrigerating system comprising a heat insulated cabinet adapted to be cooled by the circulation of air internally thereof, said cabinet having a door opening formed therein, adapted to render the contents thereof available, a refrigerant evaporating unit within said cabinet for cooling said air therein and disposed immediately inside said door opening, a sheet metal baflle facing said door opening and covering the front of said evaporating unit for obstructing the latter from view through said door opening, said baflie having an opening formed therein rendering said evaporating unit accessible, means for detachably securing said baffle to the front end of said evaporating unit and to a wall of said heat insulated cabinet for supporting said evaporating unit within said cabinet, and means for detachably supporting the rear end of said evaporating unit.

9. A refrigerating system comprising an evaporating unit having a pair of conduits wound to form a double thread, said conduits at one end of said unit being connected together for open communication between them, means for supplying liquid refrigerant to the opposite end of one of said conduits, and means for conveying refrigerant from the opposite end of the other of said conduits.

10.,A refrigerating system comprising a tubular shell and a pair of conduits forming a double thread around it, adjacent ends of said conduit being connected, means for supplying liquid refrigerant to the opposite end of one of said conduits, and means for conveying refrigerant away from the opposite end of the other of said conduits.

11. A refrigerating system having an evaporating unit comprising a helically wound conduit, said conduit comprising a pair of parallel spaced tubes connected at one end of the conduit and open at the opposite end and forming apair of concentric helices one embraced within the other, means for introducing refrigerant into the open end of one of said tubes, and means for conducting refrigerant from the open end of the other of said tubes.

12. A refrigerating. system comprising an evaporating unit including a plurality of sleeves positioned in superposed relationship, a refrigerant conduit, comprising a pair of parallel and adjacent tubes interconnected adjacent one end, wound successively around said sleeves, means for introducing refrigerant into one of said tubes at the end of said conduit opposite the point of connection of said tubes, and means for conducting refrigerant from the other of said tubes at the end of the conduit into which said refrigerant is introduced.

JOHN R. REPLOGLE. 

